| Abstract: | Hyaluronate could be labelled in vivo with 32P]phosphate. 32P]UDP in an alpha-glycosidic linkage constituted the reducing end of membrane-bound hyaluronate. The UDP is liberated during further chain elongation, indicating that chain growth occurs at the reducing end. 3H]Uridine could be incorporated into hyaluronate during synthesis on the isolated membraneous fraction from 3H]UDP-GlcNAc and 3H]UDP-GlcA, confirming the identification of UDP as a constituent of membrane-bound hyaluronate. These results led to a model of hyaluronate chain elongation at the reducing end by alternate addition of the chains to the substrates. Membrane-bound pyrophosphatases or 5'-nucleotidase are suggested as modulators of hyaluronate synthesis. |
